Tooth cavities are caused by plaque, a sticky substance that binds to teeth. Plaque is a combination of:
- bacteria
- saliva
- acid
- food particles
Everyone has bacteria in their mouth. After eating or drinking foods with sugar, bacteria in your mouth turn sugar into acid. Plaque starts forming on your teeth soon after eating or drinking anything sugary. This is why regular brushing is important.
Plaque sticks to your teeth, and the acid in plaque can slowly erode tooth enamel. Enamel is a hard, protective coating on your teeth that protects against tooth decay. As your tooth enamel weakens, the risk for decay increases.
Everyone is at risk for cavities, but some people have a higher risk. Risk factors include:
- too many sugary or acidic foods and drinks
- a poor oral hygiene routine, such as failing to brush or floss daily
- not getting enough fluoride
- dry mouth
- eating disorders, such as anorexia and bulimia
- acid reflux disease, which can result in stomach acid wearing down your tooth enamel
Cavities develop more often in the back teeth, according to the Mayo Clinic. These teeth have grooves and openings that can trap food particles. Also, these teeth are sometimes harder to reach when brushing and flossing.